With continuous development of the Internet, services of people on the Internet impose an increasing high requirement for transmission quality on the Internet, and then an openflow network emerges, where the openflow network is a new network that supports a network innovation research.
If a DHCP client in an openflow network needs to obtain an IP address, when the DHCP client starts, the DHCP client broadcasts a DHCP discover packet that is used to acquire the IP address. Then, a controller in the openflow network performs broadcast processing on the received DHCP discover packet according to a rule for forwarding an ordinary packet. Finally, after receiving the DHCP discover packet, a DHCP server in the network sends, to the DHCP client, a DHCP offer packet that includes the IP address allocated to the DHCP client so that the DHCP client acquires the IP address. Alternatively, information such as an address of the DHCP server may be manually pre-configured in the controller of the openflow network so that if the DHCP client sends the DHCP discover packet to request to acquire the IP address, the controller may generate, according to the pre-configured information such as the address of the DHCP server, a forwarding rule that is used to indicate a network path for acquiring the IP address by the DHCP client, and in this way, the DHCP client acquires the IP address according to the network path indicated by the forwarding rule.
However, if the DHCP discover packet is processed in a form of broadcasting, another DHCP client and a switch in the network both receive the DHCP discover packet, which wastes network bandwidth and lowers network efficiency. If a method in which the information such as the address of the DHCP server is manually pre-configured is used, once the information such as the address of the DHCP server is modified, configuration information of the controller needs to be manually modified, which brings great inconvenience for people′ maintenance.